1. Field
Embodiments described herein relate to a semiconductor storage device comprising an arrangement of memory cells, the memory cells configured to store data by change in a resistance value of a variable resistor, and a manufacturing method thereof.
2. Description of the Related Art
Recently a resistance change memory device in which a variable resistor is used as a storage element attracts attention as one of subsequent candidates of a flash memory. It is assumed that the resistance change memory device includes a resistance change memory (ReRAM: Resistive RAM) in its narrow definition, in which a recording layer is made of transition metal oxide and a resistance-value state of the recording layer is stored in a nonvolatile manner, and a phase change memory (PCRAM: Phase Change RAM), in which the recording layer is made of chalcogenide or the like and resistance value information of a crystal state (conductor) and an amorphous state (insulator) of the recording layer are utilized.
In the memory cell of the resistance change memory device, a cell array is formed by stacking the variable resistor and a rectifying element such as a diode at intersections of bit lines and word lines, without using a transistor. Thus, a high-density memory cell array can be constructed. Furthermore, arranging this kind of memory cell array to be stacked three-dimensionally makes it possible to achieve a large capacity, without increasing cell array area.
In order to achieve the large-capacity memory cell array, it is necessary that a desired current flows even in a fine wiring. Therefore, it is necessary to reduce a resistance of the wiring.